Various types of protective coating materials have been used to improve the abrasion resistance and hardness of polymer surfaces( e.g., polycarbonate resin). For example, Ishigaki et al. improved the scratch resistance of polymethylmethacrylate (PMMA) by utilizing silane compounds as coating materials (Jpn. Kokai Tokkyo Koho JP 63 48,364). Komatsu et al. used a mixed inorganic composition of zirconate-silicate with a SnO.sub.2 sol as an antistatic and scratch resistance coating material (Jpn. Kokai Tokkyo Koho JP 63,152,675). Nishiuchi et al. also obtained an abrasion resistant and glossy coating material from a mixed system of alkali metal oxides (Jpn. Kokai Tokkyo Koho JP 63,992268). Yamada et al. used zirconium-containing organosiloxanes as hard coating materials which were based on a 1:1 molar ratio of Zr(OBu).sub.4 with Si(MeO).sub.3 H and ethylacetoacetate as the chelating agent (Jpn. Kokai Tokkyo Koho JP 64 01,769 [89 01,769]). A pencil hardness value 4H was observed for the Yamada et al. system. Based on the same composition without Zr(OBu).sub.4, the pencil hardness value was reduced to only an HB value. The disclosure of these references describe coatings, which provide good adhesion of coatings on polymer, but which are limited to inorganic systems with no organic component.
U.S. Pat. No. 4,929,278 also discloses various sol-gel derived coatings on plastics which are also inorganic in nature and do not contain organic moieties.
U.S. Pat. No. 4,746,366 to G. Philipp et al. describes the formation of scratch-resistant coatings, which can be applied to plastic substrates, which are formed by the hydrolytic polycondensation of at least one titanium or zirconium compound (such as tetraethyl titanate or tetrapropyl zirconate) and at least one organofunctional silane. In these systems, the organic moiety has a single silane functionality at one end which is capable of hydrolytic polycondensation with the titanium or zirconium compound.